Mostrando recursos 221 - 240 de 288

  1. Modelos econométricos para la detección del fraude en el seguro del automóvil

    Ayuso Gutiérrez, Mercedes
    RESUMEN: El reconocimiento por parte del sector asegurador de la existencia de fraude en las reclamaciones de siniestros es ya un hecho. Hace escasos años, las entidades preferían ignorar la presencia del problema considerándolo un factor ineludible de riesgo. Hoy en día, saben que no pueden obviarlo, sobre todo teniendo en cuenta la influencia que posee en la evolución del número y coste medio de los siniestros. A pesar de que la actuación de las compañías aseguradoras es cada vez más notable, se echa de menos la existencia de tratamientos metodológicos exhaustivos que realicen un análisis estadístico de la información que aparece...

  2. Demand for Internet access and use in Spain

    Cerno, Leonel; Pérez Amaral, Teodosio
    The goal of this paper is to analyze a new phenomenon: Internet demand in Spain. To do so, we use a new high quality data set and advanced econometric techniques for estimating Internet demand functions, incorporating the socio-demographic characteristics of the individuals. We begin with a graphic analysis of the data, searching for relationships between the different characteristics. Then we specify and estimate two econometric models, one for broadband access at home and another for Internet use intensity. We also find that 25.2% of the Spanish population accesses the Internet at home, but less than half uses broadband connection. This demand...

  3. Localización, crecimiento y externalidades regionales. Una propuesta basada en la econometría espacial

    Vayá Valcarce, Esther
    RESUMEN: La presente tesis se enmarca en la línea de investigación sobre cuestiones relativas al crecimiento y la convergencia regional iniciada en los últimos años en el seno del grupo de Anàlisi Quantitativa Regional (AQR), el cual se enmarca en el Departamento de Econometría, Estadística y Economía Española. La existencia de un grupo de investigación de análisis regional como el citado no es sino una clara evidencia de la relevancia que la ciencia regional ha adquirido en los últimos años. En este sentido, las regiones se han convertido en las principales protagonistas, ganando terreno a los países como centro de atención. Una...

  4. Risk and returns around bond rating changes: New evidence from the Spanish Stock Market

    Abad Romero, Pilar; Robles Fernández, María Dolores
    This study analyzes the effect of corporate bond rating changes over stock prices. We explore the effects over excess of returns and systematic risk. Rating changes by Moody´s, Standard and Poor´sor FitchIBCA are analyzed. On an efficient market, these changes will omly have some effect if they contain some new information or if they are associated to a redistribution of dummy approach. Our results indicate that rating downgrades do not cause abnormal returns around the date of the announcement while upgrades cause significantly negative effect.

  5. Fast estimation methods for time series models in state-space form

    Hiernaux, Alfredo G.; Casals Carro, José; Jerez Méndez, Miguel
    We propose two fast, stable and consistent methods to estimate time series models expressed in their equivalent state-space form. They are useful both, to obtain adequate initial conditions for a maximum-likelihood iteration, or to provide final estimates when maximum-likelihood is considered inadequate or costly. The state-space foundation of these procedures implies that they can estimate any linear fixed-coefficients model, such as ARIMA, VARMAX or structural time series models. The computational and finitesample performance of both methods is very good, as a simulation exercise shows.

  6. Detección de raíces unitarias y cointegración mediante métodos de subespacios

    García Hiernaux, Alfredo; Jerez Méndez, Miguel; Casals Carro, José
    En este trabajo se propone un nuevo procedimiento para detectar raíces unitarias basado en métodos de subespacios. Nuestra propuesta tiene tres aspectos originales principales. Primero, la misma metodología puede aplicarse a series individuales o a vectores de series temporales. Segundo, utiliza una familia flexible de criterios de información, cuyas funciones de pérdida pueden adaptarse a las propiedades estadísticas de los datos. Finalmente, no requiere especificar un proceso estocástico para las series analizadas. Un ejercicio de simulación muestra que el método tiene buenas propiedades en muestras finitas y su aplicación práctica se ilustra mediante el análisis de varias series reales.

  7. A factor analysis of volatility across the term structure: the Spanish case

    Benito, Sonia; Novales Cinca, Alfonso
    We show how the term structure of volatilities for zero-cupon interest rates from the Spanish secondary debt market can be explained by a reduced number of factors. This factor representation can be used to produce time series volatilities across the whole term structure. As an alternative, volatilities can also be derived from a factor model for interest rates themselves. We find evidence contrary to the hypothesis that these two procedures lead to statistically equivalent time series, so that choosing the right model to estimate volatility is far from trivial. The volatility factor model fits univariate EGARCH volatility time series much...

  8. Econometric modeling of business Telecommunications demand using Retina and Finite Mixtues

    Marinucci, Massimiliano; Pérez Amaral, Teodosio
    In this paper we estimate the business telecommunications demands for local, intra-LATA and inter-LATA services, using US data from a Bill Harvesting survey carried out during 1997. We model heterogeneity, which is present among firms due to a variety of different business telecommunication needs, by estimating normal heteroskedastic mixture regressions. The results show that a three-component mixture model fits the demand for local services well, while a two-component structure is used to model intra-LATA and inter-LATA demand. We characterize the groups in terms of their differences among the coefficients, and then use Retina to perform automatic model selection over an...

  9. Seasonal fluctuations and dynamic equilibrium models of exchange rate

    Jimenez-Martin, Juan-Angel; Flores de Frutos, Rafael
    Most dynamic equilibrium models of exchange rate are not able to generate monthly time series with the typical properties of actual exchange rate. If the exogenous endowments in an equilibrium exchange rate model contain seasonal variations, then the exchange rate will as well. In this paper, we show how in this framework, seasonal preferences can help to remove seasonality of the exchange rate simulated time series.

  10. Seasonal fluctuations and dynamic equilibrium models of exchange rate

    Jimenez-Martin, Juan-Angel; Flores de Frutos, Rafael
    Most dynamic equilibrium models of exchange rate are not able to generate monthly time series with the typical properties of actual exchange rate. If the exogenous endowments in an equilibrium exchange rate model contain seasonal variations, then the exchange rate will as well. In this paper, we show how in this framework, seasonal preferences can help to remove seasonality of the exchange rate simulated time series.

  11. Macroeconomic and policy uncertainty and exchange rate risk premium

    Jiménez Martín, Juan Ángel; Peruga Urrea, Rodrigo
    The goal of this paper is to identify the main determinants of the risk premium in some European currency markets just before the EMU. To that extent, we start from Lucas (1982) exchange rate model and derive an analytical expression for the forward premium. This expression includes money and production variables and it is quite standard, except for the inclusion of macroeconomic policy risk. Under some standard assumptions, this formula simplifies substantially and becomes amenable to regression analysis. Then, using standard measures of money and production, as well as interest rate swap spreads as indicators of macroeconomic policy risk, the...

  12. The fit of dynamic equilibrium models of exchange rate

    Jimenez-Martin, Juan-Angel; Flores de Frutos, Rafael
    The two-country monetary model has become a fundamental tool for explaining the behavior of the exchange rate. However, the popularity of this approach is not justified by its empirical support. One of the reasons for the empirical “failure” of exchange rate models could be the econometric approach applied. In this paper, an alternative procedure for evaluating the fit of dynamic equilibrium models of exchange rate is suggested. This approach is applied to three theoretical models: Lucas (1982), Svensson (1985), and Grilli and Roubini (1992).

  13. The fit of dynamic equilibrium models of exchange rate

    Jimenez-Martin, Juan-Angel; Flores de Frutos, Rafael
    The two-country monetary model has become a fundamental tool for explaining the behavior of the exchange rate. However, the popularity of this approach is not justified by its empirical support. One of the reasons for the empirical “failure” of exchange rate models could be the econometric approach applied. In this paper, an alternative procedure for evaluating the fit of dynamic equilibrium models of exchange rate is suggested. This approach is applied to three theoretical models: Lucas (1982), Svensson (1985), and Grilli and Roubini (1992).

  14. Component versus tradicional models to forecast quarterly national account aggregates: a Monte Carlo experiment

    Marrero, Gustavo A.
    Econometric models applied to observed data, specified and estimated using traditional Box-Jenkins techniques, have been widely used to forecast Quarterly National Account (QNA) aggregates. We assess the extent to which an alternative forecasting procedure, based on component models, improves the forecasting accuracy of traditional methods. Component models distinguish between the stochastic processes underlying the low- and the high-frequency component of time series, while traditional methods do not. Relationships between QNA aggregates and their coincident indicators are often significantly different for diverse frequencies, as suggested by even an informal examination of empirical evidence. Under these circumstances, a Monte Carlo out-of-sample experiment reveals that...

  15. Component versus tradicional models to forecast quarterly national account aggregates: a Monte Carlo experiment

    Marrero, Gustavo A.
    Econometric models applied to observed data, specified and estimated using traditional Box-Jenkins techniques, have been widely used to forecast Quarterly National Account (QNA) aggregates. We assess the extent to which an alternative forecasting procedure, based on component models, improves the forecasting accuracy of traditional methods. Component models distinguish between the stochastic processes underlying the low- and the high-frequency component of time series, while traditional methods do not. Relationships between QNA aggregates and their coincident indicators are often significantly different for diverse frequencies, as suggested by even an informal examination of empirical evidence. Under these circumstances, a Monte Carlo out-of-sample experiment reveals that...

  16. Characterizing the optimal composition of government expenditures

    Pérez Sánchez, Rafaela María
    This paper extends the neoclassical growth model with productive public capital by including an infrastructure efficiency index, which is assumed to depend on a public choice variable, in particular, the share of public spending allocated to productive public consumption. A golden rule for the allocation of public expenditure between productive consumption and investment is specified. Under this framework, the observed path for the stock of infrastructures and the proposed efficiency index in the US economy during the last fifty years have been close to optimal: a lower stock of infrastructures has been accumulated, but it has been used more efficiently. Este...

  17. The welfare cost of business cycles in an economy with nonclearing markets

    Portier, Franck; Puch González, Luis Antonio
    In this paper we measure the welfare cost of fluctuations in a simple representative agent economy with nonclearing markets. The market friction we consider involves price rigidities and a voluntary exchange rationing scheme. These features are incorporated into an otherwise standard neoclassical growth model. We show that the frictions we introduce make the losses from fluctuations much bigger than in a frictionless environment.

  18. Unit root tests under time-varyng variances

    Cavaliere, Giuseppe
    The paper provides a general framework for investigating the effects of permanent changes in the variance of the errors of an autoregressive process on unit root tests. Such a framework — which is based on a novel asymptotic theory for integrated and near integrated processes with heteroskedastic errors — allows to evaluate how the variance dynamics affect the size and the power function of unit root tests. Contrary to previous studies, it is shown that under permanent variance shifts, the conventional critical values can lead both to oversized and undersized tests. The paper concludes by showing that the power function of the unit...

  19. Limited time series with a unit root

    Cavaliere, Giuseppe
    This paper develops an asymptotic theory for integrated and near-integrated time series whose range is constrained in some ways. Such a framework arises when integration and cointegration analysis are applied to persistent series which are bounded either by construction or because they are subject to control. The asymptotic properties of some commonly used integration tests are discussed; the bounded unit root distribution is introduced to describe the limiting distribution of the first-order autoregressive coefficient of a random walk under range constraints. The theoretical results show that the presence of such constraints can lead to drastically different asymptotics. Since deviations from the...

  20. Identificación de modelos para series temporales mediante métodos de subespacios

    García Hiernaux, Alfredo
    Esta tesis trata los problemas más habituales en la identificación de series temporales económicas. Siguiendo a Casals ["Métodos de Subespacios en Econometría", Tesis doctoral, Universidad Complutense de Madrid, 1997], afrontamos estas cuestiones desde un punto de vista original, ya que partimos de los llamados métodos de subespacios. Estos procedimientos, que son de uso relativamente común en otros campos como ingeniería o física, tienen ciertas ventajas respecto de los métodos actualmente utilizados en el análisis de series temporales. El trabajo contiene algoritmos basados en técnicas de subespacios implementados con el objetivo de modelar tanto procesos univariantes como series múltiples. Primero, detectan...

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